The present invention relates to weighing scales and more particularly to scales of the beam balance type in which a scale beam is pivotably supported on a beam fulcrum post and a load-receiving platform and support therefor are pivotably carried by the scale beam or beams.
Weighing scales of the type to which this invention pertains are customarily constructed to possess a predetermined load capacity and are initially calibrated to zero through the use of counterweights which are suspended on the beam at some convenient and effective location. The load-receiving area of the weighing platform is given a predetermined and fixed shape and value. Although such scales can obviously be employed in the weighing of particulate and fibrous materials it has been found that when fibrous materials of low bulk density are weighed frequently strands or fibers drape over the periphery of the weighing platform and adversely affect the accuracy of the measurement. To the contrary, relatively high bulk density material present little or no problem in terms of the accuracy of the measurement since the center of gravity of such materials coincides substantially with the vertical or longitudinal axis of the weighing platform and its support as well as with the pivot axis on the scale beam. It is not possible with existing scales to modify the size of the weighing platform to eliminate the draping over of the low bulk density fibrous materials without dissassembly of the scale and replacement of the weighing platform. In such event it would also be necessary to recalibrate the scale to zero thereby requiring that the scale be shipped back to the manufacturer and entailing additional time and expense.